Patent GB-866561-A (GB)
Title: Improved polysiloxane compositions
IPC: C08K5/57
Filed: 1959-01-30
Abstract: A lubricating composition comprises (1) a liquid siloxane co-polymer having dibromophenyl and methyl radicals bonded to Si-atoms, any remaining valencies of Si atoms being satisfied with phenyl radicals, at least 50% of the total radicals being methyl, and the dibromophenyl radicals being present in amount to give 6 to 25% by weight of bromine in the co-polymer, and (2) a tin compound which is a polymer of the unit formula:-  <FORM:0866561/IV (a)/1> a copolymer of the unit formula:-  <FORM:0866561/IV (a)/2> or a monomer of the formula:-  <FORM:0866561/IV (a)/3> or <FORM:0866561/IV (a)/4> wherein each R is a phenyl or methyl radical, n is an integer of at least 1 and each R1 is a phenyl or alkyl radical of less than 6 C atoms, (2) being present in amount such that there is from 0,5 to 2% by weight of Sn in the combined weights of (1) and (2).  The compositions may be thickened into greases with conventional thickening agents, e.g. C black, lithium-stearate and -12-hydroxystearate, alkali and alkaline earth metal salts of alicyclic substituted fatty acids, e.g. cyclohexylacetic, -propionic and butyric, g -ethyl- and a -4-ditertiary-cyclohexylbutyric, 2-cyclohexenecaproic, pentalaneacetic and cyclo-pentyl-valeric; substituted ureas of the formula Y,NH,\CO, NHY in which Y is an alkyl or aryl radical and aryl-carbamyl compounds melting above 250 DEG C. and having the formulae Y CONH Y and YNH, CO,NHY1NHCONH,Y, in which Y is an aryl radical and Y1 is an arylene radical.  Oxidation inhibitors may also be added.  Examples are given.  The polymers (2) are best prepared by reacting at a temperature below 40 DEG C. a dialkyltin dihalide with a Grignard reagent of the formula:  <FORM:0866561/IV (a)/5> where R is phenyl or methyl and X is halogen; the copolymers (2) may be made by effecting the reaction between Mg and <FORM:0866561/IV (a)/6> under conditions (i.e. above 40 DEG C.) which cause intermolecular condensation to give polymers of the formula:-  <FORM:0866561/IV (a)/7> where n is at least 1, which are then reacted with the dialkyltindihalide to give the desired copolymers.  The monomers (2) are best prepared by reacting on a steam bath R3SiOH with a dialkyltin oxide in a solvent, e.g. C Cl4. Specification 688,166 is referred to.ALSO:A lubricating composition comprises (1) a liquid siloxane copolymer having dibromophenyl and methyl radicals bonded to Si atoms, any remaining valencies of Si atoms being satisfied with phenyl radicals, at least 50% of the total radicals being methyl, and the dibromophenyl radicals being present in amount to give 6 to 25% by wt. of bromine in the copolymer, and (2) a tin compound which is a polymer of the unit formula <FORM:0866561/III/1> a copolymer of the unit formula <FORM:0866561/III/2> or a monomer of the formula [R3SiCH2]2SnR12, <FORM:0866561/III/3> or [R3SiO]2SnR12, wherein each R is a phenyl or methyl radical, n is an integer of at least 1 and each R1 is a phenyl or alkyl radical of less than 6C atoms, (2) being present in amount such that there is from 0.5 to 2% by wt. of Sn in the combined weights of (1) and (2).  The compositions may be thickened into greases with conventional thickening agents, e.g. carbon black, lithium-stearate and -12:hydroxystearate, alkali and alkaline earth metal salts of alicyclic substituted fatty acids, e.g. cyclohexyl-acetic, -propionic and -butyric, g -ethyl- and a -4-ditertiary-cyclohexylbutyric, 2-cyclo-hexenecaproic, pentalaneacetic and cyclopentylvaleric; substituted ureas of the formula YNH.CONH. Y in which Y is an alkyl or aryl radical, and aryl carbamyl compounds melting above 250 DEG C. and having the formula YCONHY and YNH.CO.NHY1NHCONHY, in which Y is an aryl radical and Y1 is an arylene radical.  Oxidation inhibitors may also be added. Examples are given.  Specification 688,166 is referred to.